Key responsive calculating machine



June 25, 1946., F. A. NIEMANN v KEY RES PONSIVE CALCULATING MACHINE Filed Oct. 10, 1941 s Sheets-Sheet l ;Junfi F. A. NIEMANN 2,402,569

XE? RESPONSIVE CALCULATING MACHINE Filed Oct. 10, 1941 6 Sheets-Sheet 2 June 1946- F. A. NIEMANN KB? RESPONSIVE CALCULATING MACHINB Filed Oct. 10, 1941' 6 Sheets-Sheet 3 June 25,1946. F. A. NIEMANN 2,402,569

KEY RESPONSIJE CALCULATING MACHINE Filed Oct. 10, 1941 6 Sheets-Sheet 4 J e 5, 1946. F. A. NIEMANN 2,402,569

KEY RESPONSIVE CALCULATING MACHINE Filed Oct. 10, 1941 6 sheets-sheet 5 MINNIE-RV jizueizt'm". figgez'z'ck c5. Niel/Lama June 25, 1946. NIEMANN 2,402,569

KEY RESPONSIVE CALCULATING MACHINE Filed 001;. l0, 1941 6 Sheets-Sheet 6 Patented June 25, 1946 UNITED STATES PATENT OFFICE KEY RESPONSIVE CALCULATING MACHINE Frederick A. Nien ann, Chicago, 111., asaignor to Felt 8; Tarrant Mtg. 00., Chicago, 111., a corporation of Illinois Application October 10, 1941, Serial No. 414,405

Claims. 1

- This invention relates in-general to calculatin tures thereof have other and more general valuable application.

' Fig.2;

In the prior power-operated, key-responsive of action has been imparted thereto, it is spring, lifted to its normal elevated position and means are provided to guard against partial or improper engagement which means also assists and enforces the lifting of the hook to its normal elevated position upon completion of a power stroke. A principal object of the invention is the pro vision of means which will guard against partial or improper engagement of the hook member with the wheel.

Another important object of the invention is the provision in a calculating machine of the character described of a novel type of toothed wheel which will insure perfect engagement of the hook member therewith under all conditions of operation.

Another important object of the invention is the provision of improved means for retaining said hook member latching means in released position, and of automatic means for releasing said retaining means and returning said hook member latching means to normal position.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, when taken in connection with the accompanying drawings, discloses a preferred embodiment thereof. 1

In the drawings,

nally through a calculating machine embodying the features of the instant invention, and showing the mechanism associated with an individual denominational order of the machine in normal or inoperative position; v

Fig. 2 is an enlarged fragmentary view similar to Fig. 1, with parts omitted, showing the parts in normal or inoperative position;

Fi 3 is an enlarged fragmentary view showing the position of the hook member and hook latching means, and latch release means in Fig. 4 is a detail, transverse, vertical section taken substantially on the line 4-4 of Fig. 2:

Fig. 5 is a view similar to Fig. 2 showing the mechanism in the position which it assumes immediately following the depression of a key;

Fig. 6 is a view similar to Fig. 3 showing the position assumed in Fig. 5; I

Fig. 7 is. a detail, transverse, vertical section taken substantially on the line 'l-'! of Fig. 5;

Fig. 8 is a detail, transverse, vertical section taken on the line 8-8 of Fig. 5;

Fig. 9 is an elevational view taken on the line 9-4 of Fig. 8; I

Fig. 10 is a view similar to Fig. 2 showing the position which the mechanism assumes during operation at the beginning of the release and return of the hook and the power trip mechanism latch member to normal, operative position;

Fig. 11 is a view similar to Fig. 3 showing the position assumed by the parts in Fig. 10;

Fig. 12 is a detail fragmentary view of the hook, wheel, and guard means showing the position of the parts prior to release of the hook from the wheel;

Fig. 13 is an enlarged detail elevational view showing the toothedwheel mounted upon a power shaft'taken from the opposite side of the wheel shown in Fig. 1;

Fig. 14 is a 'detail sectional view of the toothed wheel taken substantially on the line 14- of Fig. 13;

Fig. 15 is a detatilsectional-view taken substantially on the line I5l5 of Fig. 13;

Fig. 16 is a detail sectional plan view taken sub- Figure 1 is a vertical section taken longitudi- 86 dead center;

- rear end to a lateral Fig. 20 is a view similar to P18. 17 showing the position or the parts assumed in Fi 10; and

Fig. 21 is a view similar to Fig. 18 showing the position of the parts in prior constructions.

Referring to the drawings, and more particularly to Fig. 1, the instant invention is embodied in a power-actuated key-responsive calculating machine of the character shown and described in the patents referred to earlier herein. The working parts are mounted within a casing, generally indicated by reference numeral 20, having a keyboard 2] in its upper portion. Sound deadening material 22 is or may be provided to line the casing in whole or in part. A plurality of keys 2: are arranged through the keyboard 2i which are adapted to be selectively manually depressed to determine the digital degrees of the adding or calculating movements of the machine. These keys 23 are arranged in laterally spaced denominational orders, although only one such order o keys and the mechanism controlled and actuated thereby is illustrated herein.

Each order of keys controls the digital actua tion of the associated denominational order of ac-- cumulator mechanism, the details of which are not shown in the drawings as they are not believed necessary to an understanding of the present invention. It may be pointed out, however, that each denominational order of the accumulator mechanism includes a pinion 2,4 rotatably mounted upon a shaft 25 which extends through partition plates 26 arranged between the several. organizations of partsassociated with each de nominational order ofthe machine.

The adding is accomplished upon depression of a desired key and corresponding depression of a rack sector 21 which is in mesh with pinion 2d of the accumulator mechanism. It will be understood that the rack sector and the control and actuating mechanism therefor is duplicated for each denominationa1 order of the calculatin chine.

The rack sectoris mounted upon a shaft 28 which extends through the partition plates and is adapted to be moved downwardly on an idle or setting stroke in amount determined by the digital value of the key depressed, thi amount increasing in graduating steps from one to nine.

The downward movement of the sector is accomplished by an electric motor, generally indicated at 29, which through suitable gearing continuously drives a main power shaft 31, and is returned on its adding stroke by an actuating spring 32, all as fully described in said prior patents.

A toothed wheel 33 is fixed upon the power shaft 3| for each denominational order or column of keys and such said toothed wheel is adapted to be engaged by a hook it pivotally connected on a stub shaft 85, to the rear end of a bar or actuating link 35; The rear end of the link It is also pivoted on said stub shaft 3!, connecting it to the upper end of an upstanding guide arm 31 in turn pivoted on a cross-shaft r pivot member 3! extending through the partition plates 25. The link .36 is pivoted at its other or front end to one arm 38 of a suitable compensating clutch mechanism, enerally indicated at ll, which is mounted on the shaft 28. The rack sector Ills also connected to the slip clutch mechanism ll. The spring 32 is anchored at its forward end at 2 to the adiaoent partition plate 20' and is connected at its extension 43 of the bar or Referring to Fig. 1, depression of any key 22 causes the hook it to be depressed into encasethe clutch mechanism, the sector into set position. The depression of a key 23 causes its shank It to engage and depress the top bar I! of a parallel motion device, which is pivoted at the front at 46 and at the rear at 11 to levers ll and 49. The levers 48 and #5 are pivoted in turn upon cross shafts 5! extending through the partition plates 25. The bottom bar or link 52 of the p rallel motion device is pivotally connected to lever 48 at $3 and to lever 45 at 54. It will be understood from the prior patents referred to hereinbefore that theparallel motion device is normally held in elevated position and that the device is so constructed that depression of any key 23 results in the bar 45 being moved downwardly in the direction of the key shank M, and in the bar 52 being moved forwardly (to the right in Fig. l). a set distance.

The rack sector 21 is pivoted upon a cross shaft 28 extending through-the several denominational orders of the machine, as earlier explained, and is pivotaily connected at 55 to the forward end of a link '56. The rear end of the link 55 is plvotallv connected at I! to a downward extension on a movement controlling bar 58. The bar 53 is mounted for longitudinal sliding movement on the adjacent partition plate 26, and is provided with a plurality of stop lugs extending laterally into the path of the key shanks M and spaced progressively further back of the key shanks from the front to the rear of the machine. Consequently, downward movement of the rack sector 21 will be limited to a distance proportionate to the digital value of the particular key 23 which has been depressed.

As earlier explained, the rack. sector 21 is com nected to a slip clutch mechanism ii pivotally connected to link 3E which is in turn pivoted adjacent its other end on stub shaft 35 connecting it to the upper end of arm 31 The hook 34 is pivotally mounted at its front end on the stub shaft 35, and is adapted to be moved downwardly in responseto the depression of a key :23, in a manner to be later described. into engagement with the toothed driving wheel 33 secured to the power shaft 3 i.

Since the power shaft is rotating in a counterclockwise direction, viewing Fig. 1-, engagement of the hook it with the toothed wheel 33 'h lli pull the link 38 toward the rear of machine (to the left in Fig, 1) a set or uniform distance and until the hook is automatically disengaged from the toothed wheel, in a manner to be described more iuliy hereinafter, The link 35 extends the actuatingspring 32 and moves the rack sector 21 downwardl on an idle stroke a variable amount. depending upon the digital value of the key depressed. Release of the hook at permits the spring 32 to return the rack sector 21 to its normal position of Fig. 1, in which return movement it imparts the degree oi digital advancement to the accumulator that corresponds to the value of the key 23 depressed. The slip clutch 4! permits relative movement between the link 38,- which has a set increment of action imparted thereto, and the rack sector 21, which is stopped at selected points by the movement controlling bar 58, to enable the accomplishment of this result.

A downwardly extending dog 58 (Figs, 1 and 2) is pivotally mounted at it on bar of the key-operated parallel motion device hereinbefore described. Aspring ti attached at one end toan arm of bar 45 and at the other end to the dog II yieldingly holds a stop shoulder 82 on the dog wheel 33, to prevent premature depression of another key in the same denominational order and to prevent return of the dog 53 under sharp or staccato. stroke before the hook has opportunity to engage the toothed wheel, the following mechanism, more fully described in the above mentioned United States Letters Patent No. 2,063,962, is provided. Briefly that mechanism comprises a latch member 84 pivotally mounted on the bar 52, as shown at in Fig. 2, and yieldingly held against a suitable stop pin 64a on the bar 52 by a spring 88 connected at one end to the lever 43 (Fig. 2) and at the other end to the latch member 84. The latch member 84 is provided with a short engaging leg 61 which engages the upper surface of a laterally projecting shoulder 88 on the dog 53 when the latter is depressed, as shown in Figs. 5 and 10. The engaging leg 81 is normally positioned out of engagement with and rearwardly of the shoulder '68. Such latching of the dog 83, the parallel motion deviceand the key 23 in depressed or operated position results from the. accompanying forward movement of the bar 82 upon which the latch 84 is pivotally mounted. During such forward movement of the bar 52-, the latch member 84 is rotated in a clockwise direction, viewing Figs. 1 and 10, as later more fully described, against the action of the spring 86 and until the engaging leg 81 clears the shoulder 88 on the dog 59. The spring 88 then functions to swing the latch member 84 in a counter-clockwise direction into the latching position shown in Fig. 5.

The following mechanism is provided to automatically release the dog 53 Just prior to release of the hook 34 from the toothed wheel 33 and, since such mechanism is fully disclosed in the above mentioned United States Letters Patent No. 2,021,393, it will be only briefly described herein. The dog latch member 64 is provided with. a finger 89 and a second downwardly extending leg 89a, the lower portion of the finger 88 being disposed in the path of movement of a laterally extending in I on an upward extension ll of the guide arm 31, when the latch 64 is in its operative or forward position of Fig. 5. Rearward-movement (to the left in Fig. of the guide arm 31, which is caused by engagement of the hook 34 with the toothed wheel 33, results in the pin Ill moving the engaging leg 61 of latch member 34 out of engagement with the dog 33, against the action of the spring 66, just prior to the release of the hook 34 from the wheel 33. Such release of'thedog 53 from the engaging leg 8.1 will enable the return of the former, together with the key 23 which was depressed and the parallel motion device, to the normal posi- 'tion of P18. 1.

Depression of the dog 53' by a key 23 accom- Viewing Fig. 16, it will be seen that the hook member 34 comprises a mainhook portion having a cross bar or extension 12 formed adjacent its forward end and extending horizontally above the main portion to join the main portion with a leg 6 13 lying parallel therewith, The main portion of the hook 34 is provided. with a tall 14 which is adapted to engage the lateral extension 43 of the link 38 (Figs. 2 and 5) to limit upward movement of the rear end of the hook member, or clockwise movement thereof in the drawings, relative to the bar. The leg I3 terminates at its rearward end in a, tail ortion 15 which cooperates with a lateral extension or foot 16 on a spring-lifted lever 17 (Figs. 2 and 5). The lever 11 is pivotally mounted on the stub shaft 38 intermediate the legs of the hook member 34 (Fig.

, l6), and is provided with a lateral extension 18 at its forward end to which the upper end of a spring 13 is secured. The lower end of the spring 19 is anchored to a shaft 80 extending through the partition plates 28. The rear end of the lever 11 terminates in a lateral extension or shelf 8! (Fig. '16) with which the lower end of the dog 59 cooperates.

A second lever 82 (Figs. 4 and 16) is also pivoted on the stub shaft 35, between the legs of ,the lever l1; and terminates at-its rearward end in a pair of opposed, upper and lower, lateral extensions or shelves 83 and 84, respectively. The lower shelf 84 extends outwardly and under the main portion of the hook 34, while the upper shelf 83 extends inwardly and slopes upwardly in a rearward direction for a purpose to be later described. A lateral extension provided at the forward end of the lever 82 is connected by a spring 85 to the guide arm 31 to urge the lever 82 and hook'34 in a clockwise direction, viewing Fig. 2. A torque coil spring 88 (Figs. 2 and 16) is mounted on the stub shaft 35 with one end 36a engaging against the forward surface of the cross bar 12 of the hook 34. The other end 86?) of the coil spring 86 engages against the rear surface of the lateral extension 18 (Fig. 2) of the spring-lifted lever 11. It will be seen that the spring 86 functions to urge the hook 34 in a, counter-clockwise direction, viewing Figs. 2 and 5 of the drawings, relative to the lever 11.

With the hook 34, levers TI and 82, and springs 13, 85 and 86 arranged as above described, the spring 19, which is much stronger than spring 86, functions to lift the free end of lever 11 upwardly to sustain the hook 34 normally out of contact with the toothed wheel 33 and in the normal or elevated position of Fig. l. Depression of any key 23 causes the dog 58 to abut against the shelf 8! and depress the lever 11, swinging it in a counter-clockwise direction (viewing Figs. 1, 2 and 5) against the tension of the spring 13. The initial movement of the lever 11 by the dog 59 relievesthe hook 34 of the force exerted by the spring 19, since the spring 85 their functions to retain the hook in raised position, through the agency of the lever 82 and the shelf 84 formed thereon, and the foot 13 on the lever I1 is .moved out of contact with the tall 15 on the leg 13 of hook 34. Such depression or counter-clockwise movement of the lever ll relative to the hook 34 also compresses the ends of the torque coil spring 88 together to increase the tension thereof. Just prior to complete'depression of lever ll, the tension of the spring 88, as

will be presently explained hereinafter, has been increased to a point where it is much greater than that of the spring 35, and the spring 38 r 7 depressed position until the hook is moved downwardly by tensioned spring 86. It will be seen from Figs. 1 and 2 that the leg 59a of dog latch N is disposed in contact with the rear edge or upwardly sloping shelf 83 on spring lever 82. Upon initial depression of a, key 23 which urges the hook downwardly and the bar 52 forwardly, the dog latching member 84 is restrained against forward movement with the bar 52 and is rotated in clockwise direction against-the tension or its spring 58, by the engagement of the leg 89a with the rear edge of sloping shelf 83 of spring lever 82 until the key has been sufiiciently depressed to properly tension spring 88, at which time the shell 03 is moved downwardly out of en agement with the leg "(I and spring 65 returns the dog latching member to the latching position of Fig. 5. Accordingly, incomplete depression of a key will not effect either latching of the dog 59 in its depressed position of Fig. 5, or engagement of the hook, with the toothed wheel 33.

Means are provided for delaying engagement of the hook 34 with the toothed wheel 33 until the maximum tension of the spring 88 has been secured. A hook latch lever, generally indicated at O1 and having an upstanding arm 88, is pivotaJly mounted on a cross shaft 89 and is provided with a tall piece 99 which is normally yieldably held in engagement with the under surface of the shaft 38 (Figs. 1, 2, 5 and by a spring 9|. The spring II is coiled around the shaft 89, with one end engaging against the forward edge of the upstanding arm 08 or lever 81 and the other end engaging a suitable collar 92 on a transverse shaft 93 (Figshl, 2 and 5) Ari arm 94 projecting rearwardly and upwardly from upstanding arm 83 terminates in a lateral extension or shelf 95 (Figs. 3, 6 and 11) and the upper end 01 the arm 88 is provided with a similar extension or shelf 86. The rear shelf 95 is normally positioned beneath a lateral extension or shelf 91 (Figs. 1, 2 and 16) provided on the hook 34. Upon partial depression of a key 23, with the attendant depression of dog 59, the hook H is moved downwardly until the extension 91 engages shelf 95 delaying the dropping of the hook into engagement with wheel 33 until shelf 55 is moved out of engagement with extension 91 as will be presently described,

The shelf 55 of the arm 94 of the latch lever 81 is adapted to be moved forwardly, just prior to complete depression of any key 23 and dog 59, to release the hook 3i and allow it to drop into engagement with the toothed wheel 33. This release of the hook latch lever 81 is delayed as long as possible, through means which may be broadly described as hook latch lever actuating inechanism, and is accomplished in the following manner. A hook-shaped member indicated generally at (Figs. 2, 5 and 10) is pivoted intermediate its ends at 89 to a downward extension lull of 9.

gitudinal adjustment of the hook latch lever actuating mechanism which will be later fully described. The hook member 58 is normally held in operative position as shown in Figs. 1 and 2 by a spring I01 which is connected at one end to an upwardly extending arm ID! of the hook member 98, and at its other end to a suitable exten sion I09 formed on the bar 52.

When all of the parts are in the normal position of Figs. 1 and 2, the hook portion MS of the hook latch release member 98 is spaced rearwardly from the shelf 98, on the latching lever 81. When any key 23 is depressed, the resulting for ward movement of the hart! first carries the hook portion 103 into engagement with the shelf 95 (Figs. 5 and 6), and then, in the final portion of the depression, the hook portion I03 oi the hook member 98 rocks "the latching lever I! forwardly to its release position of Figs. 5 and 6.

The shelf 95 of the latching lever 87 is accordingly moved out from under the lateral extension 51 on the hook 314 to permit the latter to be engaged with the rotating toothed wheel 33. Since the bar M is retained in the iorward or operative position of Fig. 5 through the agency of the dog 59 and the dog latch it, earlier described, the hook-shaped member 98 will hold the hook latching lever- B! in released or inoperative position, against the action of spring 9!, as shown in Fig 5.

Means are provided for-timing the hook latch actuating mechanism. Viewing Figs. 2, 5, B and 9, it will he noted that the bell crank ill! has a rearwardly extending arm I Ill which is secured to the bar 52 by means of an eccentric stud iii. The stud H I has an enlarged portion or cam suriaee H: which is adapted to be rotated within an elongated aperture I I3 (Fig. 9) formed in the arm H0. The reduced end I of the stud passes I through a suitable aperture formed in the bar bell crank IOI which is plvotally connected at Hi2 suitable groove or slot ll! (Fig. 7) Iormed in the io'wu'dedge thereof which serves to guide the member 98 and to prevent any lateral movement of the hook portion M3. The groove I08 is of such depth as will permit the maximum ion- 52 and is fastened to a blue spring steel cup washer H5 in any suitable manner. The cup washer It provides a constant "pressure upon the stud Ill and rigidly holds the arm, 1 ill in position upon the bar 52. The head portion lilo is provided with two list surfaces illh to facilirotation of the stud iii. Upon rotation oi the stud, the cammed surface iii will pivot the arm H0 about its pivot point on and camp hook; latch release memher Bil to he move forwardly or bacirwardly within the long. limits oi the elongated aperture il to i desired adjustment thereof relative to bar ti t time the movements of the hook". latch in Bl. The slot Hill a rlier described, is of depth to perli'iit to longitudinal iidjllii jf Means are provided for moving the lever actuating mechanism upwardly,

in a clockwise direction, against the action of the spring Ml to release the hook latching lever ti.

and permit it to returned by spring ti to normal or operative position, in advance of the release of the dog latch. mber Bil. This means comprises the pin 10 which extends throng the extension ll of the guide arm 31 and co; with the curved, lower surface Hill of the hook member 98. The pin in is provided with a lil (Figs. 2, 4,5 and 10) which maybe in thereon in any suitable manner, a spacing v. i H8 being interposed between the roller ii! and the extension ll of arm 31. This lower surface of the hook-shaped member 88 is so curved that rearward movement of the arm 1! and pin II. as earlier described, from the position oi Figs. 1 and 2 to the position shown in Fig. 10. will lift the hook-shaped member i l out 01' engagement with the shelf 98 of the hook latch lever 81. The lever 81 is thus returned to its operative position of Fig. by the spring 9i well in advance of the release of the hook 34 from the toothed wheel 33, so that there can be no possibility of unintended or accidental re-engagement of the hook with the toothed wheel by the spring 86.- The point in the cycle of operations at which such release of the hook latch lever 81 is efiected may be advanced or delayed, within limits, by moving the hook-shaped member 98 either forwardly or backwardly, respectively, relative to the lever 52 by adjustment of the earlier described arm IIO of bell crank IOI. Since the hook latch lever 81 is returned to operative position before, the depressed key 23 and associated mechanism are released and returned to their normal position,

proper operation of the hook 34 will be insured upon redepression of the key or subsequent depression of any of the other keys 23, because there can be no possibility of the hook being depressed simultaneously with the depression of the dog 59,

thereby assuring the desired tensioning of the spring 86 in the next operation. As the dog latch member 84 is released from the dog 59 by the pin "I0, the bar 52 is returned rearwardly under the movement of the hook 34 into engagement withthe rotating toothed wheel 33 regardless of the speed of depression of a key 23, it has been found desirable to provide a toothed wheel of such construction that proper engagement of the hook member therewith will be had regardless of the portion of the wheel with which the hook may first come into contact. Referringparticularly to Figs. 2, 13, 14 and 15. the toothed wheel 33 comprises a hub H9, a main toothed disk I20 and an auxiliary toothed disk I2I. The two disks I20 and I2I are mounted on a reduced portion of the hub H9 and are held in sliding contact with each other by a spacing washer I22 against which the reduced end portion of the hub is upset (Fig. 14). The outer surface of the main disk I20 is preferably cut away and abuts against a flange I23 formed on the hub H8. The cut away portion of the main disk I20 is provided with a pair of outwardly extending lugs I24 which engage within slots I25 formed in the outer periphery of the flange I23. The main toothed disk I20 is accordingly rigidly secured to the hub .I I0, and

the auxiliary toothed disk I 2| is rotatable relative thereto. A pin I 23 is secured in any suitable manner to the main disk I20 and extends outwardly, through an aperture I21 in the auxiliary disk I2I, which aperture is slightly longer than the diameter of that portion of the pin I28 disposed therein to permit limited rotationof the auxiliary disk I2I relative to the main disk I20. A- spring I20 is anchored at one end to the pin I28 and at the other end to a pin I29 which is secured in any suitable manner to the auxiliary disk I2I.

The main disk I20 of the wheel 33 is provided with ten teeth I which slant rearwardly of the machine in the direction of rotation of the wheel and are rounded off at their outer ends to produce a half round surface, this serving like a' reinforced pin or lantern wheel. The auxiliary disk I2I is also provided with ten 'teeth I3I which are similar in all respects to the teeth I30 and coincide laterally therewith, except that the outer end surfaces of the teeth I 3| are flattened and the leading edges thereof are pointed, as best shown in Fig. 13. In the normal position of the several parts of the wheel '33, the pointed ends of the teeth I3I are held in advance of the teeth I30 by the spring I 28,'as shown in Figs. 2 and 5. After complete engagement of the hook 34 with the wheel 33, the auxiliary disk I2I is moved opposite to the direction of rotation thereof and against the action of the spring I28 to the position shown in Fig. 20. In this latter position, the pointed leading edges of the teeth I3I are laterally alined with the leading surfaces of the teeth I30, andsuch movement of the auxiliary disk I2I relative to the main disk I20 is caused by the nose of the hook 34 which is extended laterally to engage the teeth of both of the disks. The toothed wheel 33 is rigidlysecured to the power shaft 3| by apin I32 which extends 30" clockwise direction about the shaft 35 as a pivot.

In most instances,'as the wheel 33 is rotating and the hook 33 is thus depressed, the wheel will be so positioned at the instant of engagement of the hook therewith that the nose of the latter will fall between the teeth of the wheel and be picked up and carried rearwardly by the next following pair of teeth I30, I3I. In some cases,

however, the hook 34 may come into contact with i the wheel 33 in one of three other possible ways.

The first of these three possibilities is where the wheel 33 is so positioned at the instant of first contact of the. hook 34 therewith, that the lower edge of the nose of the latter falls against the top fiattened'surface of one of the teeth I3I. In Fig. 18, the wheel 33 is shown in such a position. Whenever such a condition obtains, the

top surfaceof the contacted tooth I3I will cam the nose of the hook 34 up andover the associated tooth I30 to permit the hook to fall be tween said teeth and the next following pair of referred to.

The second of the three possibilities is where the falling of the hook 34 is so timed relative to the rotation of the wheel 33, that the pointed leading edge of a. tooth I 3| engages against the hook at some point along the substantially verti-' cal surface of the nose portion thereof, as shown in Fig. 19. It will be noted that while Fig. 19

surface of the nose portion of the hook, it will functionto cam the hook downwardly into complete and proper engagement with the toothed 11 wheel, whereupon continued rotation of the wheel 33 will cause the tooth I 3| to yield as shown in Fig. 20.

The last ofthe three possibilities is where the engagement of the pointed leading edge of a tooth I3I is made directly with the lower end or dead center of the nose of the hook 34. In this event, the leverage of the tooth I3I and of the tooth I30 after it has been rotated for a short distance equal to the difference in the widths of the teeth III and I30 against the tension of spring I29, will be insufficient to cam the hook downwardly into full engagement with the wheel 33. When this condition occurs, the hook 34 will be carried rearwardly by the toothed wheel 33. While the probability of the hook becoming so engaged with the toothed wheel is rather remote, such engagement might take place, so that guard means,

similar to thosedescribed in the patents earlier mentioned, are provided for insuring complete and proper engagement of the hook and the toothed wheel under such. circumstances.

This guard means comprises a pivoted arm I33 (Figs. 1, 12 and 17) mounted upon an appropriately arranged shaft I34 and having its forward end held up against a spacer on a tie rod I33 by a spring I33. The forward portion of the arm I33 terminates at its lower end in a laterally extending shelf or shoulder I31. The under surface of the shelf I31 is beveled or rounded off, as is the upper surface of the lateral extension 91 on the hook member 34, so that engagement of the latter with the former, when the hook is carried rearwardly, will result in the hook 34 being cammed downwardly thereby into full engagement with the toothed wheel upon continued rotation of the wheel.

As earlier explained, the engagement of the hook 34 with the rotatingtoothcd eel i3 Jilliaparts the power to the ineclimlisni to on" till sector 21, as determined by the individual of the associated denominational order of mecha nism. This movement is more than tufilcient to impart the maximum down stroke to the rack sector, and is accomplished by positive disengage ment of the hook 33 from the toothed wheel 33 when the former reaches a certain point in its rearward travel. The hook 34 is provided on its under surface, intermediate its ends, with a downwardly extending projection I33 (Figs. 2, 5, 10 and 12) The lower surface of the projection I33 curves upwardly and forwardly into the main body portion of the hook and is so spaced from the nose of the latter as to be contacted by the end surfaces of the teeth I 33, Ill next succeeding those engaging the nose oi the hook when the latter is moved rearwardly by the toothed wheel 33 to its position of Fig, 10. From, this point, continued rotation of the wheel 33 causes the teeth I33, I3I which are in contact with the projection I33 to lift or earn the book 34 up wardly, as shown in Figl 12, until it is positively disconnected from the wheel as it reaches its real-most position. Upon disconnection. the spring 32 iunctions to return the hook 34, bar 39, rack sector 21 and associated parts to their normal positions of Fig. l, in which return movement the rack sector imparts the degree of digital advanoement to the accumulator corresponding to the value of the key 23 which was depressed.

The guard means earlier described also constitute means for assisting and'enforcing the lifting of the hook 34 from its initially released position by the spring 13, before it is returned to its normal or forward position, to prevent accidental re-engagement of the hook with the rotating toothed wheel 33, and to insure the lateral extension 91 of the hook being properly disposed above the shelf 95 on the hook latching lever 91 when the hook reaches its normal position. This means comprises the shelf I31 0n the arm I33 and an arm or lever I39 which is also pivotally mounted on the shaft I34 (Figs. 2, 5, 10 and 12). The arm I39 is yieldably held in its normal position of Fig. 2 by a coil spring I49 which urges the arm in a clockwise direction to maintain the forward edge of a laterally extending shelf I4I provided on the arm in contact with the rear edge of the shelf I31 on the arm I33. As the hook 34 is being drawn rearwardly by the toothed wheel 33 and is being lifted out of engagement therewith by the teeth I39, I3I contacting the projection I33 thereon, as shown in Fig. 12, the lateral extension 91 on the hook raises the shelf I41 to swing the arm I39 against the action of its spring I43.

Just prior to the hook 34 reaching its initially released position, the lateral extension 91 clears the shelf I4I to permit the arm I39 to be returned to its normal position by the coil spring I40. As shown in Fig. 12, the shelf I4! normally slants downwardly and rearwardly, and, since it is moved forwardly to a certain extent in its downward movement back to normal position, and the forward edge of the lateral extension 91 slants forwardly downwardly, the rear edge of the shell l li will be disposed beneath forward of the lateral extension just prior to com oletc release the hook 34 from the wheel 33. itonseouently, since the shell i3"! is lbstantlol sion 31 will loo over these hook it is returned forward to prevent accidental 'l'E-Bl'l Fig, 21 shows the type oi Wheel used in the patents earlier referred, to he Will is provided with siirteeiti 7h 1g rounded outerends similar to wet I-"iii of disk llEIl of the instant invention. Ellie guard arm shelf spacer 234 and hook 335 are identical with similar parts shown herein, but while the lateral extension 206 of hook 235 is similar in construction to extension ill of hook 34 it is farther removed from the rear extremity of the hook than extension 91 of hook 34.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparout that variou changes may be made in the form, construction and arrangement of the parts mi Without departing from the spirit and scope of connecting device, said power member comprising a toothed wheel having a cam member yield-- ably mounted for rotation adjacent and with said wheel and for yielding in the opposite direction for eamming the said connecting device into engagement with said toothed wheel to prevent misconnection of said connecting device and said wheel.

2. In a. key-responsive calculating machine having an accumulator. an actuator for said aecumulator, and means for driving said actuator: a rotatable power member adapted to be connected to said driving means by a key-controlled connecting device. said power member comprising a toothed wheel, and a cam element yieldably mounted on said wheel for rotation therewith and limited yielding movement in the opposite direction for camming said connecting device into the path of the said toothed wheel to prevent misconnection of said connecting device and said wheel.

3. In a key-responsive calculating machine having an accumulator, an actuator for said accumulator, means for driving said actuator, and key-operated mechanism for controlling the operation of saiddriving means: a rotatable power member adapted to be connected to said driving means by a connecting device which is springpressed into engagement therewith under the control of said key-operated mechanism. said power member comprising a first wheel having teeth slanting in the direction of rotation thereof, and a second wheel disposed laterally adjacent to said first wheel and mounted thereon for yielding limited rotationin the opposite direction. said second wheel having cam teeth thereon which normally extend forwardly of the leading edges of the teeth of said first wheel and are adapted to cam said connecting device into the path of the teeth of the first said wheel. I

4. In a key-responsive calculating machine having an accumulator. an actuator therefor,

means for driving said actuator, and key operated mechanism for controlling the operation of said drivingmeans, a connecting device, a rotating toothedwheel adapted to be connected to said driving means by said connecting device which is pressed into engagement therewith under control of said key operated mechanism, a cam member yieldably mounted adjacent said wheel and rotatable therewith and yieldable a limited distance in the opposite direction for camming the said connecting device into the path of rotation of said wheel. a latch lever normally preventing engagement of said connecting device with said wheel, and means operable by said key-operated mechanism for moving said latch lever to release position during the-final increment of movement imparted to said keyoperated mechanism.

5. In a key-responsive. calculating machine having an accumulator, an actuator therefor, means for driving said actuator, and key operated mechanism for controllingthe operation of said driving means, a connecting device, a rotatable power member adapted to be connected tosaid driving means by said connecting device which is pressed into engagement therewith under control of said key operated mechanism, a cam member yieldably mounted adjacent said power member and rotatable .therewith and yieldable a limited distance in the opposite direction for camming the said connecting device into the path of rotation of said power member to prevent misconnection of said connecting device and said power member. a latch lever normally preventing engagement of said connectin device with said power member, means operable by said key-operated mechanism for moving said latch lever to release position, and means operable by said power member for releasing the moving means to permit the return of said latch lever to normal position.

6. In a key-responsive calculating machine having an accumulator, an actuator therefor. and means for driving said actuator, a power clutch comprising, a drive member. a key-controlled connecting device adapted When'operated to connect said drive member with said driving means, and an auxiliary member movable with and adjacent said drive member, said auxiliary member being yieldable a limited distance in the opposite direction and including cam means for urging said connecting device into full clutching engagement with said drive member upon operation of said connecting device.

7. In a key-responsive calculating machine having an accumulator, an actuator therefor, and means for driving said actuator, a power clutch comprising a key-controlled connecting device connected to the driving means. and a pair of rotatable members engageable by said key concontrolled connecting device adapted upon operation to connect said drive member with the driving means to actuate the latter, latch mean for normally-preventing operation of said connecting device, key controlled means for operating said latch means to release said connecting device. adjustable timing means for timin the opcrating means whereby the release of said latch m'eansis variable with respect to the operation or said connecting device, an auxiliary member movable with and adjacent said drive member. and cam means on said auxiliary member and yieldable in a direction opposite that of the movement of said drive member for urging said connectlng device into full connecting relationship with said drive member when said connecting device is releasedby said latch means.

9. In a key-responsive calculating machine, a

' key-controlled power clutch member, a rotatable power member including a rotating toothed wheel, and a toothed cam member yieldably mounted {adjacent said wheel, rotatable therewith, and yleldable in the opposite direction for camming said clutch member into clutching engagement with said power member to prevent misconnection of said clutch member. and said wheel.

10. In a key-responsive calculating machine, a key-controlled power clutch member, a rotatable toothed wheel, and a toothed element yieldably mounted on said wheel for limited yielding movement in a direction opposite that "of the rotation 01' said wheel and having cam members for camming said clutch member into the path of said toothed wheel to prevent misconnection of said clutch member and said wheel.

11. In a key-responsive calculating machine.

a rotatable clutch wheel having teeth slanting in the direction of rotation thereof, an operable clutch member normallyresiliently held out of engagement with said clutch-wheel, manually actuated means for ursins'said clutch member -15 into clutching engagement with said clutch wheel, and another wheel mounted on and laterally addacent said clutch wheel and having cam teeth normally extending forwardly of the leading edges of the teeth of said clutch wheel and yieldable 5 rearwardly from the forwardly extending position to direct said clutchmember into clutching engagement with said clutch wheel.

12. In a. key-responsive calculating machine having an accumulator and an actuator for said accumulator; means for driving said actuator including a rotatable power member, key-operated mechanism for establishing a driving connection between said actuator and said driving means including a releasable connecting device and spring means energized by said key-operated mechanism for urging said connecting device into engagement with said power member, said power member comprising a toothed wheel and a cam member yieldably mounted adjacent said wheel and rotatable therewith and "yieldable in the opposite direction for camming the said connecting device into the path of rotation of said wheel to prevent misconnection of said connecting de vice and said wheel, a movable latch lever urged to a normal position for releasably restraining said connecting device against engagement with said power member, releasable connecting means between said key-operated mechanism and said latch lever to move said latch lever from normal position. to release said connecting device when the final increment of motion is imparted to said key -operated mechanism. so as to enable the latter to 21181?" lease of said c inc is to reel to permit retail.

ment or said connectin u member except in sion oi a key. 13. In a lrewrespcnsive having power nicehmzisin, anism, actuator mechanism or" mechanism, Ma -operated n echr parted to said. actuator mechsn mechanism upon depression iii a it means under the ccntrnl oi mechanism for connecting and said actuator mechanism, ii. nectiug device adapted to he urge ling eon- .ito engagement with said power mechanism; iever normally urged to latching pcsition to reieaisaiily latch said connecting device out i m with said power inechiim connected to said moving said latch lever to r depression of a key, and cit engagement a manually gagement oi said opera.

' latch member to release eration oi men upon actuating movement of said actuator mechanism by said power mechanism upon establishment of driving connection between said actuator mechanism and the power mechanism for releasing said moving means to permit the return of said latch lever to latching position so as to prevent re-engagernent of said connecting device with said power member except in response to a second depression of a key.

14. In a key-responsive calculating machine, a rotatable power [clutch member, an operable clutch member, means including a spring yieldably holding said operable clutch member in decliitched position with respect to said rotatable clutch member, spring means for urging said operable clutch member toward clutching engagement with said rotatable clutch member, manually operable means for energizing said last mentioned spring means to overcome said first spring means, a latch lever normallyurged to latching position to releasably hold said operable clutch member in declutched position, releasable connecting means between said key-operated mechanism and said latch lever to move said latch lever from normal position to release said operable clutch member when the final increment of motion is imparted to said manually operable means so as to enable the latter to nergize said last mentioned spring means prior oi": said operable clutch member member to obtain a maximum of said opcraizile clutch member tatable clutch member, and able with said operable i rotatable clutch member gagement thereof for ing means th of said latch lever to vent reengagen in he end police to in opera,

iii. in

movement iii road'tp' inent W1 normally 1,: eventing; clutch in g g said ing means for urging an 01 her into clutching enga clutch menit l, latch said manually opera member, and means opera; clutch member from said dri during clutching engagemen ing said lateh-rncving means i to permit the return of said i position so as to prevent operable clutch member witi member except in respn 

